Combined cord connector and strain relief



July 24, 1956 w. R. FRANCIS ET AL 2,756,403

COMBINED CORD CONNECTOR AND STRAIN RELIEF Filed May 15, 1955 [)7 venors:George C. Mape/saen, Herberfl M/flm s, Wa//ace R Franc/s,

Qg W1. find/Mi The/r- Az: Cor/763g.

nited States Patent t COMBINED CORD CONNECTOR AND STRAIN RELIEF WallaceR. Francis, Milford, George C. Mapelsden,

Easton, and Herbert D. Williams, Monroe, Conn., assignors to GeneralElectric Company, a corporation of New York Application May 13, 1955,Serial No. 508,082

9 Claims. (Cl. 339-128) The present invention relates to electricalconnectors and particularly to combined electrical cord connectors andstrain reliefs for use with electrical equipment and appliances.

This invention is particularly useful in the power supply cords fortelevision receivers although it will be readily appreciated that it isnot limited to such a use, and that it is readily adaptable to resilientbushings and grommets as well as electrical connectors. At the presenttime, the connectors for such appliance cords are adapted to be attachedby means of permanent fasteners such as rivets to the removable backpanel of the television set. Thus, when it is necessary to repair theset, the removal of the back panel will automatically disconnect the setfrom the power source so as to reduce the likelihood of high voltageshocks being received by the Serviceman.

The present invention was conceived in order to eliminate theabove-mentioned rivets and the consequent labor costs by making itpossible to readily snap the connector of the cord into an opening inthe back panel so that the connector would be able to withstand pullingforces in the order of 35 pounds while making it difiicult to removewith the hands without the use of special tools.

The principal object of this invention is to provide a combinedconnector and strain relief for an electrical cord so that it mayreadily be mounted in a non-circular opening in a thin panel member.

A further object of this invention is to provide a combined connectorand strain relief for an electrical cord which is relatively easy toinsert in an opening in a panel member while being difiicult to removewithout the exertion of a large force which would tend to damage thecord or connector rather than remove it.

A further object of this invention is to provide a combined connectorand strain relief for an electrical cord having a recessed taperedportion which may be satisfactorily inserted in a non-circular openingin a thin panel member.

Our invention will be better understood from the following descriptiontaken in connection with the accompanying drawing and its scope will bepointed out in the appended claims.

Figure 1 is a top plan view of a combined connector and strain reliefembodying our invention.

Figure 2 is a cross-sectional view taken on the lines 22 of Figure 1.

Figure 3 is a cross-sectional view taken on the lines 3-3 of Figure 1.

Figure 4 is a side elevational view of the combined connector and strainrelief of Figure 1.

Figure 5 is a right-hand end view of the combined connector and strainrelief of Figure 4.

Figure 6 is a left end view of the combined connector and strain reliefof Figure 4 taken on a plane through the electrical cord.

Figure 7 is a perspective view of the combined connector and strainrelief of Figure I mounted in a rectangular-shaped opening in a thinpanel member.

2,756,403 Patented July 24, 1956 Figure 8 is a top plan view similar toFigure 1 showing a second modification of this invention.

Figure 9 is a side elevatioual view similar to Figure 4 showing thespecies of Figure 8.

Figure 10 is a top plan view of a combined connector and strain reliefsimilar to Figure 1 showing a third modification of our invention.

Figure 11 is a right end elevational view of the combined connector andstrain relief of Figure 10.

Figure 12 is a side elevational view of the combined connector andstrain relief of Figure 10.

Referring in detail to the drawing in which like elements arerepresented by the same reference numerals, Figure 1 shows a combinedconnector and strain relief 10 formed of rubber or similar elastomericmaterial secured on the end of an electrical cord 11. While theconnector 10 i shown as having recessed contacts 12, it is clear thatthe connector could as an alternative be provided with male prongswithout departing from the scope of this invention. The contacts 12 arecrimped, soldered or otherwise fastened to the conductors 22 of the cord11, and the body of connector 10 of suitable vinyl or elastomericmaterial having resilient characteristics is molded thereover. Theconnector 10 is provided with a shoulder portion 13 at one end, anannular recessed tapered or beveled portion 14 and a series oftransversely-spaced longitudinally-extending ribs or ears 15 arrangedaround the connector body and adjacent the smallest end of the taperedportion to be opposed to the shoulder 13. Each ear 15 has a slopingouter surface that is inclined generally in the same direction as therecessed tapered portion 14. This does not mean that these surfaces arenecessarily parallel to each other but rather that they are not opposedto each other. As best seen in the cross-sectional view of Figure 2, theears 15 have undercut sides 16 which reduce the width of the base of theear as it approaches the tapered section 14. Also, the pair of recesses17 which separate the ears 15 on the top and bottom of the connectorhave a depressed fioor 18 as best seen in Figure 3. Thus, each car 15may be readily deformed so that it will flow sidewise as well aslengthwise into the tapered section 14. The connector 10 is designed tobe secured in a rectangular-shaped opening 19 in a thin panel membersuch as panel 20 of Figure 7. The dimensions of the opening 19 areslightly less than the corresponding dimensions at the large end of thetapered section 14, as i shown with dotted lines 19' in Figure 1, toprovide a snug fit after assembly.

Since the connector 10 is larger in over-all size than the opening 19 inthe panel member 20, it is necessary to provide an access slot 21 in theside edge of the panel member 20 so that the cord 11 may be fed throughthe slot 21 into the opening 19 with the connector 10 located adjacentthe side of the panel not visible in Figure 7. Then a pulling force isapplied to the cord 11 so that the peripheral edge of the opening 19will obstruct the free movement of the ears 15 through the opening. Whenthe pulling force is continued, the ears 15 will be depressed by flowinginto the tapered section 14 as Well as sidewise into the recessesseparating the ears. As the shoulder portion 13 bears against the edgesof the opening 19, the cars 15 will spring outwardly from the opening tobe in the position as shown in Figure 7. The thickness of the panel 20is made equal to or slightly greater than the width of the taperedsection 14 in an attempt to eliminate all free movement between theconnector and the panel. Accordingly, it can be seen that the ears 15are of novel design to cooperate with the tapered section 14 to make itrelatively easy to insert the connector in the panel 20 while allpulling forces tending to remove the connector from the panel areresisted by the strong shoulder portion 13 which is able to support morethan 35 pounds of force applied to the cord.

In the second species of Figure 8, there is a combined connector andstrain relief molded on the end of an electrical cord 11 in a similarmanner as is shown in Figure l. The connector 30 has a shoulder portion33 as well as a recessed tapered section 34. and a series oflongitudinally extending ears 35. The shoulder portion 33 is similar tothe shoulder 13 of Figure l, and the same is also true of the taperedsections 34 and 14. However, the ears 35 are a modification of the cars15 of Figure 1. Each ear 35 is provided with an overlying tip 36 whichextends over a portion of the tapered section 34. The side walls of theears 35' are not undercut as at 16 nor are the recesses 37 provided withan undercut door as at 13 in Figure 3. The principal purpose of the tips36 of the ears 35 is' to provide the connector 39 with a strong grippingaction for engaging the edges of the opening 19 in the panel 20.However, the ears 35 would not be quite as readily deformed as theundercut ears 15 of the species of Figure l.

The two species of Figures 1 and 8 may be termed pullin connectors forthey are assembled in the panel by exerting a pulling force on the cord.The third species of Figure 10 is somewhat different in that it ispushed into the opening in the panel; therefore, it may rightly beclassified as a push-in type connector. This third connector 40 issimilarly of resilient insulating material that is molded on the end ofthe cord 11. The shoulder portion 43 is here adjacent the transversecenterline of the connector, while the longitudinally extending cars arearranged on the free end of the connector to be compressed or deformedwhen a pushing force is applied to the connector 40 until the taperedsection 44 is located within the opening 19 of the panel member 29.Since the connector 40 may be pushed into the opening in the panelmember, the access slot 21 may be eliminated. A slight disadvantage ofthis design is that the series of ears 45 must also resist the pullingforces applied to the conductor 11 in the same manner as the shoulderportions 33 and 13 in the other two species. Accordingly, the connector40 is not designed for the same rugged use as species one and two sinceit is not able to support as great a pulling force as the shoulderportions 13 and 33 of Figures 1 and 8 respectively, The ears 45 are notundercut as at 16 in Figure 2 nor are the recesses 47 depressed as at 18of Figure 3 since the ears must by themselves support all of the pullingforce's transmitted through the cord 11.

In the species of Figure l, the cars 15 are more readily deformed thaneither the ears 35 or 45. Also, the shoulder portion 13 is able to'resist a pulling force greater than that of cars 15 while equal to theresistance provided by shoulder portion 33 of Figure 8. Thus, thespecies of Figure l is the preferred embodiment of our invention.

Accordingly, having described our invention of a combined cord connectorand strain relief, it should be readily understood by those skilled inthis art that we have provided a reliable strain relief means for theconnector so that it may be easily attached in an opening in the panelmember and cannot be removed by the hands without the use of specialtools. While we have chosen to illustrate our invention in connectionwith a connector having recessed contacts, it will be readily apparentthat this strain relief means may be incorporated in resilient bushingsthat are to be attached to panel members and that it has found itsgreatest use with bodies that are to be inserted in non-circularopenings in a panel member. The resulting structure is ofr'elativelysimple design which is easy to mold in mass productionquantities but the greatest advantages are enjoyed by the manufacturerwho Will purchase a cord set having a connector embodying our inventionbecause of the ease of assembling the connector without the use ofpermanent fasteners.

Modifications of this invention will occur to those skilled in this artand it is to be understood, therefore, that this invention is notlimited to the particular embodiments disclosed but is intended to coverall modifications which are within the true spirit and scope of thisinvention.

What we claim as new and desire to secure by Letters Patent of theUnited States is:

1. An electrical cord having a combined cord connector andstrain reliefsecured thereto, comprising a body of resilient material with agenerally rectangular transverse cross-section, a recessed taperedportion symmetrically arranged at least on the top and bottom of thebody, there being a shoulder portion at the large end of the taperedportions, and a plurality of transversely spaced longitudinallyextending cars at least on the top and bottom of the body adjacent thesmall end of the recessed tapered portions, the backs of the said earsbeing inclined in the same direction as the angle of the related taperedportion.

2. An electrical cord having a combined cord connector and strain reliefsecured thereto, comprising a body of resilient material with agenerally rectangular transverse cross-section, a continuous recessedtapered portion extending around the body, there being a shoulderportion on opposite sides of the body at the large end of the taperedportion, and a series of transversely spaced longitudinally extendingears on opposite sides of the body adjacent the small end of the taperedrecess, the backs of the said ears being inclined in the same directionand substantially at the same angle as that of the recessed taperedportion.

3. In combination with a thin panel having an opening therethr'ough, anelectrical cord having a combined connector and strain relief securedthereto, comprising a body of resilient material having a generallyrectangular transverse cross-section with a recessed tapered portionextending around the body, a shoulder portion symmetrically arrangedadjacent the large end of the recessed tapered portion, and a series oftransversely spaced longitudinally extending ears symmetrically arrangedadjacent the small end of the recessed tapered portion, the backs of thesaid ears being inclined in the same direction and substantially at thesame angle as that of the recessed tapered portion, while the size andshape of the large end of the tapered portion are substantially equal tothat of the opening in the said panel so that the body will be scarcelyembraced therein.

4'. A body member as recited in claim 3 wherein the tips of said earsoverlie a section of the said tapered portioii so as to provide a stronggripping force to hold the body member in the opening in a panel andprevent the swiveling movement of the body member with respect to thepanel.

5. An electrical cord having a combined cord connector and strain reliefsecured thereto, comprising a body of resilient material with agenerally rectangular transverse cros's-section, a recessed taperedportion, symmetrically arranged at least on the top and bottom of thebody, there being a shoulder portion at the large end of the taperedportion, and a plurality of transversely spaced longitudinally extendingears at least on the top and bottom of the body adjacent the small endof the recessed tapered portion, the backs of the said ears beinginclined in a converging manner in a direction away from the taperedportion.

6. In combination with a thin panel having an opening therethrough, abody member of resilient material that is adapted to be fastened in thepanel opening, said body having a generally rectangular transversecrosssection with a recessed tapered portion extending around the body,a shoulder portion symmetrically arranged adjacent the large end of therecessed tapered portion, and a series of transversely spacedlongitudinally extending ears symmetrically arranged adjacent the smallend of the recessed tapered portion, the backs of the said ears beinginclined in the same direction and substantially at the same angle asthat of the recessed tapered portion, while the size and shape of thelarge end of the tapered portion are substantially equal to that of theopening in the said panel so that the body will be securely embracedtherein.

7. In a body member of resilient material that is adapted to be fastenedin an opening in a panel member, a recessed tapered portion locatedbetween a shoulder on one side and a series of longitudinally extendingears on the other side adjacent the smallest end of the tapered portion,the backs of the said ears being inclined in the same direction andsubstantially at the same angle as that of the recessed tapered portion,while the said ears have undercut sides to reduce the width of the earsat the base of each so as to facilitate the easy insertion of the bodymember into an opening in a panel.

8. An electrical cord having a combined connector and strain relief ofresilient material secured thereon, said connector comprising a bodyhaving a shoulder portion at one end in cooperation with an annularrecessed tapered portion adjacent thereto, and a series oflongitudinally-extending transversely-spaced deformable ears havingtheir end portions aligned with the other side of the tapered portion,the smallest end of the tapered portion being adjacent the said ears,the back surface of each of the said ears being inclined in generallythe same direction as the tapered portion, the ears having undercutsides to reduce the width of the ears at the base thereof while thespaces between some of the adjacent ears have a depressed floor so as tofacilitate the easy insertion of the connector into an opening in a thinpanel member whereby the panel would be clamped between the saidshoulder portion and the ears.

9. An electrical cord having a combined cord connector and strain reliefsecured thereto comprising a body of resilient material with a generallyrectangular transverse cross-section, and a series of transverselyspaced longitudinally extending ears extending around one end of thebody, an annular recessed tapered portion with its smaller end adjacentthe said series of ears, and a shoulder portion bordering on the otherside of the annular tapered portion which is thus located between thesaid ears and shoulder, the backs of said ears being inclined in thesame direction and substantially at the same angle as the taper of therecessed portion.

References Cited in the file of this patent UNITED STATES PATENTS1,287,285 Garnrneter Dec. 10, 1918 1,577,539 Polk Mar. 23, 19261,601,255 Marra Sept. 28, 1926 2,115,495 Mapelsden Apr. 26, 19382,196,785 Takigucki Apr. 9, 1940 2,421,456 Judisch June 3, 19472,441,907 Schrnitt May 18, 1948 2,494,814 Huth Jan. 17, 1950 2,668,316Sturtevant et al Feb. 9, 1954 2,697,817 Fratila Dec. 21, 1954 2,704,355Holton Mar. 14, 1955 2,711,522 Goodwin June 21, 1955

